You can Favorite a world so you can go to it again and again and you dont have to seach and find it. 

And we can have accounts so our worlds in single player can go with us where ever we want and if we add a friend system the system can be more secure. and other Possibilities! 

Or mabey place the name of the creator under thier servers in multiplayer mode so they can get apreciation 

Just some Ideas by Meh. :3